Leica M39 Screw Mount vs Bayonet Mount

[carlprad]

Hello

I am interested in purchasing some older Leica lenses to use on my Leica M8.

However, I find that they often come in Leica Srew Mount M39, and you have to get an adapter to use with the M8.

Is there any difference in functionality, once the lens is attached to an adapter, between the screw-mount and bayonet-mount lens. In other words, once I attach the Screw Mount lens to the appropriate "screw-mount to bayonet-mount" adapter, will the lens function exactly as the bayonet-mount lens?

a) will it focus the same way?
b) will it handle the same way?
c) does it have a tendency to come off its adapter?

Finally, are there any benefits to buying a bayonet-mount lens over a screw-mount lens?

Thanks

 

[Roger Hicks]

A screw mount lens functions the same, on or off the adapter, and is no more inclined to come off the adapter than off a screw-mount camera. The only advantages of bayonet-mount lenses are that most of them are newer designs and (of course) you don't need an adapter. There are a very few designs where the bigger throat of the M is necessary for big back glasses, but of course those lenses aren't available in the screw mount anyway. I cheerfully use a mixture of screw and bayonet lenses on my Ms.

Cheers,

R.

 

[Phil_F_NM]

I use mostly LTM lenses on my M8 and M9. I'm working towards getting a pre ASPH 35 'lux but that's a ways into the future. I love the screwmount lenses due to low cost 9for the most part) and very respectable imaging qualities. Some lenses are only available in LTM and a few of them have pretty special ways of drawing an image. Not that it's better, but different. Technically, probably much worse, but this still has the capacity to be an art, so we can choose the tools that we want to use to capture our images.

The ONLY drawback I've seen from using screwmount lenses is that most of them have a close-focus of .9 meters at the closest. You might find a few that get closer but they are the exception to the rule. Don't let this discourage you from shooting screwmount lenses though. Some of them are truly fantastic (the 35 Summarons, 50mm f/1.4 Canons, all of the Nikkors) and hold their own against the most current designs. Personally, I just love the way they make an image & I love shooting through a lens made 50 or more years ago and capturing photos which look great. I love saving some money too!

Have fun,
Phil Forrest

 

[carlprad]

What about a good adapter

What about a good adapter

Thanks for the info.

What about a good LTM M39 to Bayonet mount adapter?

I see a ton of them listed on Ebay. Some only cost about $5. I even found some with the 6-bit coding indents built into them.

I really like the idea of having an adapter with 6 bit coding indents. It should make coding the lens really easy.

However, I'm new to all of this and know nothing about quality. Can someone suggest some good adapters?

Thanks

 

[Roger Hicks]

Original Leica or current Voigtländer adapters are far and away the most reliable. Making an adapter isn't rocket science, but equally, it is precision engineering and it's easy to make something that looks like an adapter but is too thick/thin, won't seat properly, is 39mm x 1mm rather than 39mm x 26 tpi, etc.

Cheers,

R.

 

[dee]

I use screw mount lenses exclusively , but have to buy an adapter with a cut out for the Elmar focus lock , even though mine is an SRB version .
I have now invested in a Contax RF / M mount to use my Kiev / Contax lenses as I prefer vintage lenses .

 

[carlprad]

I am thinking of getting a Leica 50mm Summarit 1.5 Screw-mount lens.

I think all the Summarit 1.5 have a focus lock, or at least the one I am looking at seems to have a focus lock.

Does this mean I need a special kind of adapter?

 

[Ben Z]

Original Leica or current Voigtländer adapters are far and away the most reliable. Making an adapter isn't rocket science, but equally, it is precision engineering and it's easy to make something that looks like an adapter but is too thick/thin, won't seat properly, is 39mm x 1mm rather than 39mm x 26 tpi, etc.

Cheers,

R.

+1. Especially with the M8 and M9, even the slightest deviation from specified flange-to-focal plane distance will show up as, at the very least, loss of contrast, due to slight mis-focus.

Which brings up another subject: collimation tolerances. Older Leica lenses may have been overhauled at some point and not necessarily rebuilt to perfection. It pays to get a reasonable inspection period allowed by the seller.

I am thinking of getting a Leica 50mm Summarit 1.5 Screw-mount lens.

I think all the Summarit 1.5 have a focus lock, or at least the one I am looking at seems to have a focus lock.

Does this mean I need a special kind of adapter?

It depends on whether the back of the focus lock retrudes past the lens flange or not. My 50mm f/3.5 Elmar's does, my LTM 50mm f/2 Summicron's does not. My Hove book doesn't show a clear shot of the Summarit, but the one of it's predecessor Xenon looks like the lock should clear the adapter, so a full-circumerance adapter should be ok. That's good because then it can be coded. The cutaway-type adapters can't.

 

[carlprad]

Ben Z

Thanks for the great info. Here is a link to the lens I'm looking at:

http://cgi.ebay.com/SUMMARIT-5cm-F1...Filters_JN&hash=item53e45502c9#ht_4658wt_1141

Do you think i can get a full-circumerance adapter?

Also, where can I buy a good 6-bit adapter? There are some on Ebay that come with the indents ready for coding. However, I don't know which brands are good quality and which are junk.

Thaks

 

[Ben Z]

It definitely will be fine with the cut-out adapter, and the lens won't benefit from coding other than to put the focal length in the EXIF data (and even then the maximum aperture will be wrong because there is no code for f/1.5).

Now the bad news: The Summarit takes a 41mm screw-in filter (or a special 43mm push-on type). You may find it something of a challenge to get an IR filter to fit. If you can find one of the Leitz 41mm or 43-push-on filters you might be able to swap-in an IR glass. Probably a B+W 486 in 40.5mm would fit the 41mm mount. I'm not sure of the actual glass size in the 43-push-on. If you're not handy, you probably had best leave the swapping to someone who can do it without scratching the IR glass coating.

Frankly (and please pardon me for interjecting my opinion where it wasn't asked for) US$700+ is far more than I'd consider paying for a Summarit with admitted "front coating marks". I paid $650 for an early-80's Summilux with perfect glass about 3 years ago. IMO if you want a vintage ultra-fast 50, I'd keep an eye out for an f/1.4 Nikkor-SC in Leica screw mount. That one takes a standard 43mm filter, and unless it's been abused, the front glass on those usually tends to be good. They didn't suffer from the soft front coatings of contemporary Leitz lenses.

 

[Muddy]

I have 50's Summarit it takes B+W 41E filter and e-bay non-brand 40.5mm snap on lens cap. It's one of a very good Leica 50 mm lens with unique character.

 

[carlprad]

Ben Z

Are you saying that I need the cut-out adapter, or can I use a full-circumference adapter?

Ok, so far I have:

1) B+W Makes a 41mm UV filter
2) Voightlander adapters are very good
3) I don't need to worry about coding the lens
4) I shoot mostly outdoors and never really use an IR-filter on my m8

Now all I need is a lens hood/shade I can afford.

I read that someone got away with putting a 40.5mm crew-on hood on their Summitar, due in part to the the Summitar's unique "Thread Pitch". Has Anyone else experienced this compatability?

Thanks all for your help thus far.

 

[Ben Z]

Ben Z

Are you saying that I need the cut-out adapter, or can I use a full-circumference adapter?

You can use either one.

4) I shoot mostly outdoors and never really use an IR-filter on my m8

I shot my M8 mostly outdoors too, and I definitely needed IR filters. Otherwise, green plants came out a yellowish color...which was nearly impossible to correct in post, because grass in the same shot came out normal green.